From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 037AAC43142 for ; Tue, 26 Jun 2018 21:39:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6FB93223D5 for ; Tue, 26 Jun 2018 21:39:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="r0OGvdr4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6FB93223D5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753150AbeFZVjS (ORCPT ); Tue, 26 Jun 2018 17:39:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:59698 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752175AbeFZVjQ (ORCPT ); Tue, 26 Jun 2018 17:39:16 -0400 Received: from mail-it0-f47.google.com (mail-it0-f47.google.com [209.85.214.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E6A6C23EBF; Tue, 26 Jun 2018 21:39:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1530049156; bh=6D7WDbeFEDS6ujrxcRrtT4Oh+52tXITCPW1f0T0P5AI=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=r0OGvdr4TGwqpcQ46zKs2ohVoXNC4FAngKHaLHd5VeSWoM0J9/FfkgKt+HkrsjrtV TyjXKHO9SS4+QvByynghMxhu3zsRcvR/VVzlQVpdt5yPLZt0YnTSWIqZdqf2KPFXeQ n10EgRqzohNXLsOnLbGb6YWPC4lJXQJGWllwjMlU= Received: by mail-it0-f47.google.com with SMTP id a195-v6so4518373itd.3; Tue, 26 Jun 2018 14:39:16 -0700 (PDT) X-Gm-Message-State: APt69E08V5ZQ+loC6zYCZq5LVl884N5GCCA/MhSTyDf1PxianvJGDpP2 oZ79ucHuPovn17J11iJrxGGh6tPEsByiOVkyxw== X-Google-Smtp-Source: AAOMgpdyUE/rD6vzXEgiWtrgzg3bn/7TltbC+b00u+cd7MfV944CkiBV6LLYNHNeWOPmnwDQy7a358fAER8Io+8VWgs= X-Received: by 2002:a24:798f:: with SMTP id z137-v6mr2750002itc.19.1530049155573; Tue, 26 Jun 2018 14:39:15 -0700 (PDT) MIME-Version: 1.0 References: <20180619212744.794-1-daniel@zonque.org> In-Reply-To: <20180619212744.794-1-daniel@zonque.org> From: Rob Herring Date: Tue, 26 Jun 2018 15:39:04 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH RFC 0/4] Adding DT functionality to w1 busses To: Daniel Mack Cc: zbr@ioremap.net, Mark Rutland , szabolcs.gyurko@tlt.hu, devicetree@vger.kernel.org, "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 19, 2018 at 3:27 PM, Daniel Mack wrote: > In order to fully move battery-supplied devices over to devicetree, the > onewire subsystem must get some updates. > > Currently, the w1 bus system works like this. Device families, such as > battery controllers etc, are registered to the w1 core. Once a master > device is probed, it starts scanning the bus. Slave devices that are > revealed through this scan and that match previously registered > families are then registered, and their .add_slave() callback is > invoked. > > Some devices, such as the ds2760, use that callback to call > platform_device_alloc() at runtime with a fixed device name to > instanciate their only user. That user does the actual work, while the > slave device merely functions as an I/O proxy. In the user > implementation, the w1 slave device is accessible through > dev->parent. Looks to me like you are letting the driver structure define the DT structure. This detail is all irrelevant to DT. > > Now, for devicetree environments, this has to change a bit. First, slave > devices need to have a matching table so they can be listed as sub-nodes > of their master bus controller. Second, the core needs to match the > entries in these tables against the sub-nodes of the master node. > These two are trivial to do. > > The next question is how the w1 slave device and its user(s) are linked > together. I'm proposing a DT layout with the following example: > > onewire { > compatible = "w1-gpio"; > > w1_slave: slave@0 { > compatible = "maxim,w1-ds2760"; > }; > }; > > battery-supply { > compatible = "maxim,ds2760-supply"; > w1-slave = <&w1_slave>; > }; This should just be one node and a child of the 1-wire master. Rob